Can you disconnect the AGR (Automatic Gearbox) from a 105hp direct-injection (PD) engine of a Golf 5?

Hello everyone!!!

I'm getting my new Golf Sportsline with 105 horsepower next week!

I was wondering if it's still possible to bypass the EGR valve, as it was with older TDI models, without triggering any error messages? Does the trick of disconnecting the clutch connector still work?

Sure, no problem.

Best regards, mat.

Mat wrote:

Next week, I'm getting my new 5-series Golf Sportline with 105 horsepower PD!!! wollte mal fragen ob es wie bei den alten tdis auch möglich ist die agr abzuklemmen OHNE DAS FEHLERMELDUNGEN AUFTRETEN? funktionert der trick mit dem kupplungstecker auch noch???

Hi,

Based on my "only Euro 3-compliant" car, which triggers the error light even with a dead AGR (though thankfully doesn't go into limp mode), I suspect you're in a similar situation.

But what exactly do you mean by disconnecting the clutch connector (what for??)

Hello, It's not that simple to disable the AGR (selective catalytic reduction) system, as it is monitored as part of the OBD (on-board diagnostics) system for diesel vehicles, which is installed in the Golf V.
So, the MIL (Malfunction Indicator Lamp, which is the check engine light) will start to stay on continuously.
It will likely soon be possible to prevent this through the use of fake information.

Hi,

I think what's meant by the clutch issue is that he wants to disconnect the connector from the clutch switch and ensure that the MSG (presumably a control module) always sees "clutch not depressed."

That would negate the shock absorption and would likely provide a bit more acceleration when starting hard, but it would also likely damage the clutch and transmission more quickly.

I would avoid doing that, especially since it's not great even when using cruise control.

Best regards,

Jan.

mersente wrote:

Hello, It's not that easy to disable the AGR, as it is naturally monitored as part of the OBD system for diesel engines, which is installed in the Golf V. So, the MIL (Malfunction Indicator Lamp, which is the check engine light) will start to stay on continuously. Da wird es sicherlich auch bald möglich sein das durch einen Fake zu unterbinden.

Hi,

The principle would be quite simple: mix the EGR control signals, in a "smoothed" form, with the mass airflow sensor (MAF) signal.

I've been thinking about a circuit design that would accomplish this with the least amount of effort... but I haven't found a truly convincing solution yet.

'Umm, I don't want to interrupt your 'smoothed-out malfunction lamps' , but how about simply inserting a metal plate between the EGR valve and the intake manifold? It's a purely mechanical solution that has been proven thousands of times.'

Or is the volumetric flow rate of exhaust gases already being monitored by an air mass meter (AMM)?

Or does the engine control unit already trigger a warning if the mass airflow sensor value becomes suspiciously high (because there is a lack of exhaust gases and therefore more air is being drawn in)?

Hi,

@SeatArosa{m Exactly. That's why the question at the beginning, and that's why Ulf's considerations. Newer TDIs will detect it if you disable the AGR valve. It's quite simple - if the AGR control system doesn't cause a change in the mass airflow sensor (MAF), then something is broken.

@Ulf: I know you don't like digital technology... but a small AVR microcontroller could do a great job.

Best regards,

Jan.

I thought so. Clever, those guys at VAG .

But there is still a purely mechanical solution:
The EGR valve no longer mixes exhaust gas into the intake air, but instead introduces fresh air. It's essentially a switched bypass for the mass airflow sensor (MAF). This would likely require a small, separate air filter.

Well, I think the electronic solution would be more feasible with less effort. A small analog circuit with 10 components on a stripboard the size of a matchbox – and that's it. It's just about artificially attenuating the analog signal from the flow meter.

Thank you for the quick responses!!!

Okay, I thought that the AGR issue wouldn't be that simple! If it can only be fixed with a correction circuit, I'll probably leave it for now (because of the warranty and so on...).

@ jan6k, yes, you are right, that's what I meant. However, I don't believe that it's harmful in any way. This type of damping wasn't used anywhere before. According to VW/Audi group, it only serves as a comfort function to prevent rattling.

Best regards, mat.